As you've probably guessed, we're really big on keeping things accessible around here for the under 4ft crowd.
It's the bit of Montessori that's the most relevant right now and in the parlance of the philosophy, it's referred to as Practical Life.
One of Baz's favorite things to do is turn lights on when we're working in a room and he can reach the kitchen switches, but none of the others. So I purchased some of these bad boys:
Light switch extenders. We started with two: one in his bedroom and one in his bathroom. Then I added two more: one in the hallway and one in his play area (the switch is actually in the office, but it controls the fixture above his table. Our house was built in 1949 and updated in 1969 and has been existing in a state of benign neglect ever since. We don't question things like switch placement lest our heads explode.)
Anyway - they have made all the difference - he can control his environment without needing to either whine at me or drag a chair around my hardwood floors. Everyone wins.
I have yet to find these in an actual store (not for lack of trying) so you'll have to get yours off Amazon, like I did.
Then sit back and watch your child's sense of confidence and capability grow. Hooray for autonomy!